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net/mlx5e: Prepare non-linear legacy RQ for XDP multi buffer support

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mlx5e_skb_from_cqe_nonlinear creates an xdp_buff first, putting the
first fragment as the linear part, and the rest of fragments as
fragments to struct skb_shared_info in the tailroom. Then it creates an
SKB in place, based on the xdp_buff. The XDP program is not called in
this commit yet.

This commit contains no functional change, except the SKB is built over
the whole frag_stride of the first fragment, instead of the minimal size
required (headroom, data and skb_shared_info).

Signed-off-by: Maxim Mikityanskiy <maximmi@nvidia.com>
Reviewed-by: Tariq Toukan <tariqt@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>
This commit is contained in:
Maxim Mikityanskiy 2022-01-26 17:43:33 +02:00 committed by Saeed Mahameed
parent e89600ebee
commit 4e8231f1c2
1 changed files with 61 additions and 14 deletions
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75
drivers/net/ethernet/mellanox/mlx5/core/en_rx.c
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@ -1567,45 +1567,92 @@ mlx5e_skb_from_cqe_nonlinear(struct mlx5e_rq *rq, struct mlx5_cqe64 *cqe,
struct mlx5e_wqe_frag_info *wi, u32 cqe_bcnt)
{
struct mlx5e_rq_frag_info *frag_info = &rq->wqe.info.arr[0];
struct mlx5e_wqe_frag_info *head_wi = wi;
u16 rx_headroom = rq->buff.headroom;
struct mlx5e_dma_info *di = wi->di;
struct skb_shared_info *sinfo;
u32 frag_consumed_bytes;
u32 first_frag_size;
struct xdp_buff xdp;
struct sk_buff *skb;
u32 truesize;
void *va;
va = page_address(di->page) + wi->offset;
frag_consumed_bytes = min_t(u32, frag_info->frag_size, cqe_bcnt);
first_frag_size = MLX5_SKB_FRAG_SZ(rx_headroom + frag_consumed_bytes);
dma_sync_single_range_for_cpu(rq->pdev, di->addr, wi->offset,
first_frag_size, DMA_FROM_DEVICE);
rq->buff.frame0_sz, DMA_FROM_DEVICE);
net_prefetch(va + rx_headroom);
/* XDP is not supported in this configuration, as incoming packets
* might spread among multiple pages.
*/
skb = mlx5e_build_linear_skb(rq, va, first_frag_size, rx_headroom,
frag_consumed_bytes, 0);
if (unlikely(!skb))
return NULL;
page_ref_inc(di->page);
mlx5e_fill_xdp_buff(rq, va, rx_headroom, frag_consumed_bytes, &xdp);
sinfo = xdp_get_shared_info_from_buff(&xdp);
truesize = 0;
cqe_bcnt -= frag_consumed_bytes;
frag_info++;
wi++;
while (cqe_bcnt) {
skb_frag_t *frag;
di = wi->di;
frag_consumed_bytes = min_t(u32, frag_info->frag_size, cqe_bcnt);
mlx5e_add_skb_frag(rq, skb, wi->di, wi->offset,
frag_consumed_bytes, frag_info->frag_stride);
dma_sync_single_for_cpu(rq->pdev, di->addr + wi->offset,
frag_consumed_bytes, DMA_FROM_DEVICE);
if (!xdp_buff_has_frags(&xdp)) {
/* Init on the first fragment to avoid cold cache access
* when possible.
*/
sinfo->nr_frags = 0;
sinfo->xdp_frags_size = 0;
xdp_buff_set_frags_flag(&xdp);
}
frag = &sinfo->frags[sinfo->nr_frags++];
__skb_frag_set_page(frag, di->page);
skb_frag_off_set(frag, wi->offset);
skb_frag_size_set(frag, frag_consumed_bytes);
if (page_is_pfmemalloc(di->page))
xdp_buff_set_frag_pfmemalloc(&xdp);
sinfo->xdp_frags_size += frag_consumed_bytes;
truesize += frag_info->frag_stride;
cqe_bcnt -= frag_consumed_bytes;
frag_info++;
wi++;
}
di = head_wi->di;
skb = mlx5e_build_linear_skb(rq, xdp.data_hard_start, rq->buff.frame0_sz,
xdp.data - xdp.data_hard_start,
xdp.data_end - xdp.data,
xdp.data - xdp.data_meta);
if (unlikely(!skb))
return NULL;
page_ref_inc(di->page);
if (unlikely(xdp_buff_has_frags(&xdp))) {
int i;
/* sinfo->nr_frags is reset by build_skb, calculate again. */
xdp_update_skb_shared_info(skb, wi - head_wi - 1,
sinfo->xdp_frags_size, truesize,
xdp_buff_is_frag_pfmemalloc(&xdp));
for (i = 0; i < sinfo->nr_frags; i++) {
skb_frag_t *frag = &sinfo->frags[i];
page_ref_inc(skb_frag_page(frag));
}
}
return skb;
}